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The complete Inframail setup checklist: account creation through DNS verification, inbox provisioning, SMTP export, Instantly connection, warmup, and pre-campaign checks. Nothing skipped.
James Whitfield
Cold email infrastructure specialist, 200+ outreach systems built · Updated June 24, 2026
Last updated: June 2026 · James Whitfield, Cold email infrastructure specialist, 200+ outreach systems built
TL;DR — 7 things to know before reading
Every infrastructure problem I see in cold outreach systems — and after 200+ builds, I have seen most of them — traces back to something that was skipped or assumed to be done without verification. DNS not actually propagated. Warmup enabled but IMAP not connected. DMARC missing because no one knew what it was. SPF correct in theory but pointing to the wrong include.
The pattern is consistent: cold email infrastructure is not difficult, but it has many sequential steps with dependencies, and each unverified step creates a potential failure point that surfaces later as a mysterious deliverability problem. When an inbox that seemed fine starts landing in spam six weeks after launch, the root cause is usually something that was improperly configured at setup time.
This checklist exists as a single-pass verification: run through every item before launching campaigns, confirm each step is actually done and actually working (not just assumed to be working), and arrive at campaign launch with confidence. It is not a tutorial for how to do each step (see the other Inframail guides for step-by-step setup instructions); it is a verification system for ensuring everything is confirmed before first send.
Use Inframail for the inbox provisioning. Use Instantly for warmup and campaign management. Use Quarvio for verified contact data. Use Aimfox for LinkedIn outreach alongside email.
Verification: You can reach the Inframail dashboard without any verification prompts or billing warnings.
Common failure: Creating an account but not verifying the email, which restricts account functionality and may prevent domain addition.
Verification: Review your current plan limits in account settings and confirm they exceed your planned domain and inbox count.
Common failure: Starting setup on a trial or starter plan with inbox limits, then discovering the limits when trying to create the full inbox portfolio.
Verification: All planned sending domains are visible in the Inframail Domains dashboard.
Common failure: Adding only the first domain and forgetting to add the remaining domains before creating inboxes.
For each sending domain:
v=spf1 include:spf.protection.outlook.com -allVerification: Use MXToolbox SPF lookup (mxtoolbox.com) for each domain. The result should show a valid SPF record and pass status.
Common failure: Entering the SPF record with a typo in the include mechanism, or entering it as an A record rather than a TXT record.
For each sending domain:
Verification: Use MXToolbox DKIM lookup with your domain and selector1. The result should show the CNAME resolving correctly to Microsoft's key.
Common failure: Adding a TXT record instead of a CNAME record for DKIM. Inframail's Microsoft 365 infrastructure uses CNAME-based DKIM, not TXT-based. A TXT record at selector1._domainkey will fail DKIM verification.
For each sending domain:
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.comVerification: Use MXToolbox DMARC lookup for each domain. The result should show a valid DMARC record.
Common failure: Skipping DMARC entirely because it is optional for initial delivery. While missing DMARC does not cause immediate delivery failures, it reduces Google Postmaster data quality and indicates a lower email maturity level to receiving providers. Always add at minimum p=none.
If you want replies to cold emails to arrive at the sending domain inbox:
Verification: Send a test email to an address at the sending domain (e.g., test@getacme.com) and confirm delivery.
Common failure: Not adding MX records and then wondering why replies to cold emails are bouncing or not arriving. Without MX records, the sending domain has no way to receive incoming mail.
Verification command: Visit mxtoolbox.com, select "SPF Record Lookup", enter each domain name, and confirm the lookup result shows a valid SPF record.
Wait time if not yet propagated: 15–60 minutes. If not propagated after 2 hours, double-check that the record was saved correctly in the registrar DNS panel.
Common failure: Proceeding to inbox creation before SPF propagation is confirmed. Emails sent before SPF propagates may fail authentication, though SPF failures are soft failures rather than hard rejections in most cases.
Verification: Visit mxtoolbox.com, select "DKIM Lookup", enter the domain and selector "selector1", and confirm the result shows the CNAME resolving to a valid Microsoft DKIM key.
Wait time if not yet propagated: 15–60 minutes for CNAME records; potentially longer if your registrar is slow.
Common failure: Checking DKIM using a TXT record lookup instead of CNAME lookup. Because Inframail uses CNAME-based DKIM, a TXT lookup at selector1._domainkey will return nothing, leading to a false failure diagnosis.
Verification: Visit mxtoolbox.com, select "DMARC Lookup", and enter each domain. The result should show your DMARC policy.
Common failure: Seeing a DMARC lookup error and assuming it means the record is wrong, when the actual cause is propagation not yet complete. Wait 15–60 minutes and check again.
Verification: In the Inframail Domains section, the status for each domain shows all authentication records as verified.
Common failure: External MXToolbox lookups pass but the Inframail in-dashboard verification still shows a failure. This can happen if Inframail's verification check runs on a different DNS resolver with a different cache. Wait 10–15 additional minutes and refresh the Inframail dashboard.
Verification: In the Inframail Inboxes section, each inbox shows as active with its associated domain displayed.
Common failure: Creating inboxes before DNS verification passes in the Inframail dashboard. Inboxes created before DKIM is verified may not have DKIM signing active immediately.
Verification: Credentials are recorded in a secure location (password manager or team credentials vault).
Common failure: Not recording passwords immediately after inbox creation, then needing to reset passwords later when connecting to the campaign tool.
Verification: Open the CSV and confirm it contains email address, password, SMTP server, SMTP port, IMAP server, IMAP port for each inbox.
Common failure: Not generating the bulk export and then connecting inboxes to Instantly one at a time, which is significantly slower for portfolios of 10+ inboxes.
Verification: In Instantly, navigate to Sending Accounts and confirm every Inframail inbox shows as connected, not failed.
Common failure: Some inboxes showing as "failed" after bulk import due to credential formatting issues in the CSV. Re-connect failed inboxes manually.
Verification: In Instantly, check each inbox's connection status. If IMAP shows separately from SMTP, confirm both show as connected.
Common failure: SMTP connecting successfully but IMAP failing, which prevents warmup replies from being received and tracked. The IMAP connection is required for warmup functionality; SMTP-only connection allows sending but breaks warmup.
For each inbox in Instantly:
Verification: Open any sending account in Instantly and review the settings panel to confirm the above values are set.
Common failure: Leaving daily limits at Instantly's default (which may be higher than what new inboxes can safely send), causing new inboxes to hit limits too quickly.
Verification: In Instantly, the warmup section shows each inbox in active warmup status.
Common failure: Connecting inboxes to Instantly but forgetting to enable warmup, then starting campaigns from cold inboxes.
Verification: Check your inbox documentation spreadsheet: campaign-ready date for each inbox is at least 14 days after warmup start date.
Common failure: Starting campaigns 7 days after warmup begins because "the scores look good already." Early warmup scores can be misleadingly positive; the full 14–28 day period allows the reputation to solidify across more receiving providers.
Verification: In Instantly's warmup dashboard, all inbox scores are above 80.
Common failure: Assigning inboxes to campaigns when some inboxes have warmup scores of 60–70, which indicates incomplete or problematic warmup. Low warmup scores predict lower inbox placement rates in campaigns.
Verification: All three authentication results show "pass" in the email headers.
Common failure: All three showing "pass" in MXToolbox DNS lookups but DKIM showing "fail" in actual email headers, indicating that the inbox is not correctly using the verified DKIM key. This requires contacting Inframail support to verify the inbox-to-key association.
Verification: Test campaign analytics in Instantly show bounce rate below 2%.
Common failure: Skipping the baseline test and discovering high bounce rates only after the first live campaign has sent thousands of emails, by which point the domain reputation is already damaged.
Verification: If using Quarvio contacts, the 90% deliverability guarantee provides baseline assurance. If using contacts from other sources, run the list through a verification tool before uploading.
Common failure: Uploading an unverified contact list to the first campaign and experiencing a high bounce rate that damages the new inbox reputations before they have a chance to build history.
For the first campaign:
Verification: Review campaign settings before activating.
Common failure: Using Instantly's default shared tracking domain (track.instantlyai.com) for link tracking, which is on shared infrastructure and can have reputation issues from other users. Configure a custom tracking domain using a subdomain of one of your sending domains.
Verification: Confirm a team member is actively monitoring replies for the sending accounts.
Common failure: Launching campaigns without a reply handling process, missing positive replies, and allowing unsubscribe requests to go unprocessed.
Verification: Run each sending domain through MXToolbox Blacklist Check and confirm zero blacklist listings.
Common failure: Starting campaigns from a domain that was previously used for something else and already appears on one or more blacklists. Blacklisted domains have severely impaired delivery regardless of how perfect the DNS setup and warmup are.
Verification: Sending domain shows in Google Postmaster Tools dashboard (reputation data will only populate after you start sending to Gmail addresses).
Common failure: Not setting up Postmaster Tools until after deliverability problems are discovered, at which point historical reputation data is unavailable and diagnosis is harder.
Section 1: Account
Section 2: DNS Configuration
Section 3: DNS Verification
Section 4: Inbox Creation
Section 5: Instantly Connection
Section 6: Warmup
Section 7: Pre-Campaign
Total: 24 items. All 24 must be confirmed before the first campaign send.
| Setting | Value | Notes |
|---|---|---|
| SPF record | v=spf1 include:spf.protection.outlook.com -all | TXT record at root (@) |
| DKIM record | CNAME at selector1._domainkey | Points to Microsoft key infrastructure |
| DMARC minimum | v=DMARC1; p=none; rua=mailto:dmarc@domain.com | TXT record at _dmarc |
| SMTP server | smtp.office365.com | Port 587, STARTTLS |
| IMAP server | outlook.office365.com | Port 993, SSL/TLS |
| Inboxes per domain | 3–5 | More concentrates reputation risk |
| Warmup minimum | 14 days before campaigns | 28–60 days for full maturity |
| Warmup score minimum | 80+ before campaigns | Below 70 = stay in warmup |
| Pre-campaign bounce test | Below 2% | Run on 50–100 test sends |
| Daily sends per new inbox | 20–30 (combined warmup + campaign) | Increase after 8 weeks |
It is tempting to complete all DNS configuration for all domains simultaneously, then verify all simultaneously. The risk is that DNS problems on one domain can be confused with problems on another domain. Work through the checklist domain by domain: add DNS for domain 1, verify domain 1, create inboxes on domain 1, then move to domain 2. This makes troubleshooting clearer when a step fails.
If you are setting up multiple domains, create a separate copy of the checklist for each domain. Name each copy with the domain name. This prevents the common error of marking a step "done" for the whole batch when it is only done for one domain.
When you start warmup for a new inbox batch, immediately set a calendar reminder for 14 days later: "Warmup batch [name] eligible for campaigns. Verify warmup scores first." This prevents the scenario where inboxes complete warmup, get forgotten for weeks, and then get added to campaigns without a warmup score check.
DNS records can be accidentally modified during other changes to your domain's DNS (adding a new service, SSL certificate renewals, registrar changes). Run MXToolbox SPF, DKIM, and DMARC checks for all active sending domains quarterly, not just at setup time. Catching a broken record before it causes campaign damage is much better than discovering it after open rates drop.
Record when each domain was added to Inframail and when each inbox was created. This historical record is invaluable when troubleshooting future problems: if an inbox starts having deliverability issues 90 days after creation, knowing the exact creation date, warmup start date, and campaign start date provides a timeline for diagnosis. Without documentation, this history is impossible to reconstruct.
Symptoms: MXToolbox DKIM lookup for selector1 returns "DKIM record not found" or CNAME lookup fails.
Diagnosis steps:
selector1._domainkey (without the main domain appended, as some registrars auto-append the domain)Fix: Delete the existing record if incorrectly typed, re-add with correct type (CNAME) and host value, wait for propagation, and re-verify.
Symptoms: MXToolbox SPF lookup shows a "Multiple SPF records found" error.
Diagnosis steps:
Fix: Delete the old SPF record and keep only the Inframail/Microsoft 365 SPF record: v=spf1 include:spf.protection.outlook.com -all. If you need to include another provider, merge them into one record: v=spf1 include:spf.protection.outlook.com include:other.provider.com -all.
Symptoms: Warmup scores for new inboxes start above 80 in the first week, then drop to 60–70 in week 2–3.
Diagnosis steps:
Fix: Confirm IMAP is connected and functional. Ensure no campaign sends are happening from inboxes still in warmup. Extending warmup duration and pausing campaigns from affected inboxes.
Symptoms: MXToolbox DKIM DNS lookup passes, but the received email headers show DKIM: fail.
Diagnosis steps:
Fix: Wait 24–48 hours and re-test. If the problem persists, contact Inframail support: they can manually trigger DKIM activation for the affected inboxes.
Symptoms: After bulk importing the Inframail SMTP CSV, several inboxes show authentication failures.
Diagnosis steps:
smtp.office365.com and port is 587Fix: Re-export SMTP credentials for failed inboxes individually from Inframail and re-enter them manually in Instantly.
A verified user on Inframail reviews on G2:
"The checklist approach is the only thing that keeps setup from turning into chaos when you are setting up 10+ domains. I built my own checklist from mistakes in the first few setups: the first time, I forgot to verify DNS before creating inboxes. The second time, I forgot to enable warmup before the inboxes were added to campaigns. By the third batch, I had a checklist, and nothing got missed."
— Verified buyer on Inframail reviews on G2
A thread in r/coldemail (1,447 upvotes):
"The biggest thing I see people miss is the DKIM record type. Inframail/M365 uses CNAME-based DKIM, not TXT. If you add a TXT record, it looks fine in DNS but fails at send time. Check this specifically if you are having authentication failures and everything else seems right."
— r/coldemail, 1,447 upvotes
A reviewer on Instantly reviews on G2, where Instantly holds 4.9/5 from 2,800+ reviews:
"IMAP is the one that catches everyone. People connect Instantly to their Inframail inboxes, see the SMTP green checkmark, and think they are done. Then warmup scores stay low because the IMAP connection failed silently. Always verify the IMAP connection separately from SMTP."
— Verified buyer on Instantly reviews on G2
| Need | Tool | Notes |
|---|---|---|
| Inbox provisioning | Inframail | Microsoft 365, bulk SMTP export |
| Campaign and warmup | Instantly | Warmup scores, sending accounts |
| Verified contact data | Quarvio | Pre-verified contacts for campaigns |
| LinkedIn outreach | Aimfox | Parallel LinkedIn outreach |
How long does the full Inframail setup take from start to campaign-ready?
The technical setup (account, DNS, inboxes, Instantly connection) takes 2–4 hours per 5-domain batch. Warmup requires a minimum 14 days (28–60 for full maturity) after the technical setup is complete. Total time from start to first campaign send: 14–60 days, primarily determined by warmup duration.
What is the most important step in the Inframail setup checklist?
DNS verification before inbox creation. Inboxes created before DNS is fully verified may not have proper DKIM signing active from the start. All authentication records — SPF, DKIM, and DMARC — should show as verified in both MXToolbox and the Inframail dashboard before any inboxes are created.
Can I run campaigns and warmup simultaneously from the same inboxes?
Yes, and you should. Warmup should run continuously throughout the active campaign period, not just during the initial warmup phase. Keeping warmup active while campaigns run maintains positive engagement signals that partially offset cold outreach signals.
How many inboxes should I set up on each domain?
3–5 inboxes per domain is the recommended range. More than 5 concentrates reputation risk: if one campaign from this domain triggers complaints, all inboxes on the domain are affected. Fewer than 3 makes the per-inbox cost of the domain higher. 4 inboxes per domain is a common balance.
What warmup score should I require before starting campaigns?
A warmup score of 80 or above is the minimum for assigning inboxes to campaigns. Scores between 70 and 80 should stay in warmup-only for an additional 1–2 weeks. Scores below 70 indicate a setup problem (often IMAP failure or DNS issue) that should be diagnosed and fixed before campaigns.
Do I need Google Postmaster Tools for every sending domain?
Yes. Google Postmaster provides the only publicly available view into how Gmail is evaluating your sending domains and IP addresses. Without Postmaster Tools data, you are flying blind on the 40–60% of cold email contacts who use Gmail. Setting it up costs nothing and provides irreplaceable data once you start sending.
What should I do if authentication fails on the first test email?
Check the email headers to identify which authentication check is failing (SPF, DKIM, or DMARC). If DKIM is failing despite the DNS CNAME record passing in MXToolbox, contact Inframail support — the internal DKIM key activation for the inbox may need to be triggered manually. Do not proceed to campaign sends until all three authentication checks pass.
How often should I re-run the checklist after initial setup?
Run the authentication portions of the checklist (Section 3 items 3.1–3.3 and Section 7 item 7.1) quarterly. DNS records can be accidentally modified during other domain changes. Run the blacklist check (Section 7 item 7.6) monthly. Run warmup score reviews (Section 6 item 6.3) weekly.
What if I skip warmup and just start campaigns immediately?
Short-term: your open rates will be lower because inbox placement rates are worse for un-warmed inboxes. Medium-term: if the un-warmed inboxes receive complaint signals before building reputation, the domain reputation can be damaged quickly. Long-term: domains that get blacklisted from rapid campaign sends without warmup are difficult and time-consuming to rehabilitate. The warmup period is the most important operational protection for your infrastructure investment.
Can I use the same Inframail inboxes for multiple campaigns simultaneously?
Yes, but manage the combined daily send volume carefully. If an inbox is assigned to two campaigns and both are sending aggressively, the combined sends per day can exceed the safe limit. Ensure the total sends from all campaigns assigned to a given inbox stays within the per-inbox daily limit (20–30 for new inboxes, 40–50 for mature inboxes).
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